Air-compressor



D. M. PUTNAM AND H. M. DUNLAP.

AIR COMPRESSOR.

APPLICATION FILED JUNE 10. 1919.

1,399,151, Patented Dec. 6, 1921.

2 SHEETS-SHEET 1.

7 3mm Definer H. Putnam Harley nbunlap @Vflmaw D. M. PUTNAM AND H M.DUNLAP.

AIR COMPRESSOR.

APPLICATION FILED JUNE 10. 1919.

1 399, 1 5 1 Pat nted Dec- 6, 1921.

- 2 SHEETS-SHEET 2.

3mm Del mer' M, PuTnam ewumm Hurley 1"]. .Dun lgp UNITED, STATES,

PATENT ()FFICE.

DELMER M. PUTNAM Ann HARLEY DUNLAP, or BATTLE CREEK, MICHIGAN.

AIR-GODEIPR-ESSOR.

T 0 all 20 71cm it 172 ag concern Be it known that we, Dnminr. M. PUTNAMand Hana-Er M. DUNLAP, citizens of the United States, residing at BattleCreek, Michigan, have invented certain new and useful Improvements inAir-Compressors, of which the following is a specification.

This invention relates to improvements in air compressors.

The main objects of this invention are:

First, to provide an improveo multi-stage air compressor of the pistontype which is of large capacity.

Second, to provide an improved multistage air compressor of the pistontype in which rod packings are eliminated.

Third, to provide an improved multi-stage air compressor of the pistontype which is simple in its parts and very durable.

Further objects, and objects relating to structural details, willdefinitely appear from the detailed description to follow.

o accomplish the objects of our invention by the devices and meansdescribed in the following specification. The invention is clearlydefined and pointed out in the claims.

A structure which is a preferred embodiment of our invention is clearlyillustratec in the accompanying drawing, forming a part of thisspecification, in which:

Figure I is a side elevation of an air cornpressor embodying features ofour invention, a portion of the base being broken away.

Fig. II is a detail view mainly 'in'vertical section, on a linecorresponding to line 22 of Fig. III.

Fig. III is a detail view mainly in horizontal section on a linecorresponding to line 33 of Figs. I and II.

Fig. IV is a detail view mainly in vertical section corresponding tosection of Fig. II showing certain modifications in the compressionchamber and discharge connections.

In the drawing, similar reference characters refer to similar partsthroughout the several views, and the sectional views are taken lookingin the direction of the little arrows at the ends of the section lines.

Referring to the drawing, 1 represents the base, 2 the crank case and 3the cylinder of our improved pump. The cylinder 3 is stepped orshouldered at 4 to provide bores of different diameter, the larger bore5 being at the outer end of the cylinder and the smaller bore 6 at itsinner end. The cylin- Specification of Letters Patent. Patented D 6 1921Application filed. June 10, 1919.

Serial No. 303,227.

der head 7 is in the preferred embodiment a fiat plate. The crank shaft8 and piston rod 9 are shown conventionally. The piston, designatedgenerally by the numeral 10, has a head portion 11 coacting with thelarger bore of the cylinder and a barrel portion 12 coacting with thesmaller bore thereof of the cylinder.

The head portion 11 of the piston is provided with piston rings 13 whilethe barrel portion 12 has piston rings 14 at itsinner end. The outer endof the cylinder constitutes the primary compression chamber, while theportion ofthe larger bore at the rear of the head portion of the pistonand surrounding its barrel portion constitutes the secondary compressionchamber.

In the embodimentof our improvement shown Fi s. 1, II and III, theprimary compression chamber is provided with a dis charge passageopening centrally through the head of the piston to the secondarycompression chamber and delivering to the secondary compression chamberat the rear of the head of the piston. See Fig. II.

The piston is provided with a valve chamber 16 for valve 17. This valveis held yield ingly to its seat 18 by the spring 19. These parts arealso shown mainly in conventional form, as they form no part of ourpresent in-, vention. The inlet port 20 is provided with a check valve21. To lessen the noise, the inlet pipe 22 is connected to the crankcase 2. The discharge port 23 of the secondary compression chamber islocated at the rear of the chamber adjacent the shoulder 4. A checkvalve 24 is provided for this discharge port, and the pipe 25 leads tothe pressure tank or other delivery, as may be desired.

In the modification shown in Fig. IV,

the head 26 is provided with an inlet port 27 provided with the valve21. The dis-- charge for the primary compression chamber is through port28 in the cylinder head, pipe 29 and passages 30 and 31, the passage 31serving both as an inlet and an outlet for the secondary compressionchamber. The port 32 connecting the ports 30 and 31 is controlled bycheck valve 33. The passage 31 connects with the discharge pipe throughthe check valve 35.

With the parts thus arranged, the air is forced under pressure from theprimary compression chamber into the secondary compression chamber asdescribed, which is of much less capacity than the primary compressionchamber, owingto the space occu pied by the barrel of the piston.

The packings are of the piston rin type, so the are simple in form andvery c urable V and e ective in use, the use of rod packings beingentirely avoided by our improvements. The piston rmgslQ are disposed atthe rear of the piston pin so that the full stroke of the piston may beutilized.

To providean air tight jointjfor the piston pin and also to effectivelysupport and retain the pin, we provide the piston with opposed.b 0res.36having inwardly projecting flanges37 about them providing supports forthe tubular piston pin 38. Thus the piston pinlisiretained and tightjoints provided by means of plug-like retaining o1 adapt same asimaybedesired.

Having thus described our invention, what we claim as new and desire tosecure by Lettflrs Patent is V 1. In a multi-sta e air compressor, thecombinationof a cyhnder stepped to provide boresof different diameterswith the larger bore at thecouter end of the cylinder, a pistonhaving ahead portion coacting with said larger boreand a barrelportion-coactingwith the smaller bore, the outer end of the cylinderconstituting 'the primary compression chamber and the portion of thelarger bore at the rear of the head portion of the piston andsurrounding its barrel portion 'constitut'ingthe secondary compressionchamber, the head and barrel portions of thejpiston being provided withpiston rings, the piston rings of the barrel portion being at its innerend, a discharge passage for'gthe primary compression chamber throughthe head of the piston opening at the rear thereof, a check valve forsaid passage, an inlet valve for the primary compression chamber at theouter end of said cylindenand a valved discharge connection forsaidsecondary compression chamber at a ber, and the portion of thelarger bore at the rear of the head portion of the piston andsurrounding its barrel portion constituting a second compressionchamber, said chambers being connected for delivery from one to theother, the head and barrel portions of the piston being provided withpis ton rings, the piston rings of the barrel portion being at its innerend, a piston rod, a piston pin therefor disposed between the pistonringsoi' said piston and so that it passes from the reduced portion ofthe cylinder 'on I the outstroke of the piston, and means .for sealingthe ends of the piston pin whereby leakage from thesaid.secondmoinpression chamber through the-piston is prevented,

In witness whereof we vhave hereunto set our hands and seals."

DELMER ML PUTNAM 'L. s] HARLEY MFDUNLAP 1a. 3.

